The present invention relates to internal combustion engines and, more particularly, to an improved rotary valve mechanism and cylinder head assembly for internal combustion engines, including gasoline, diesel and other types.
The use of rotary valves with internal combustion engines has been long known. Thus, in Russell U.S. Pat. No. 1,232,849, which issued in 1917, there was proposed a rotary valve mechanism for use not only with what were then misunderstandingly referred to as "explosive motors" but also steam engines, pumps and other machinery in which valves were employed. Such arrangement included a valve member positioned above a cylinder head assembly wherein the valve member rotated upon a horizontal axis, being driven by a shaft carrying a gear wheel for geared relationship with a valve timing and driving mechanism of undisclosed construction.
In 1930, U.S. Pat. No. 1,777,464 issued to W. M. Edwards upon a rotary valve mechanism for an internal combustion engine wherein, again, the valve was positioned for rotation upon an axis parallel to the axis of rotation of the crank shaft, being driven by it through a bevel gear arrangement, and the valve being located within a finned housing. Such valve controlled intake and exhaust of gases relative to the combustion chamber.
Then, in 1933, U.S. Pat. No. 1,924,188 of C. W. Hall issued upon a rotary valve for internal combustion engines wherein, once again, a single rotary valve for each cylinder was carried on a shaft for rotation about an axis parallel to the crank shaft, there being multiple cylinders, each having such a valve on a single shaft. It was proposed to surround the valve housing with a water jacket in which coolant could circulate. Various passages were provided for flow along a path within the valve which extended along the axis of rotation. That is, there was longitudinal flow through the valve.
Not until 1966, in Yost U.S. Pat. No. 3,274,901 was there first disclosed, insofar as is known, the use of a rotary valve wherein the valve was permitted to rotate upon an axis which was perpendicular to the crankshaft. The rotary valve was provided with a flange which was permitted to rotate within the combustion chamber for opening and closing of inlet and exhaust gas passages communicating with the chamber, the valve including a central sleeve in which a helically grooved rod or core was caused to reciprocate by the piston for causing the valve and thereby its flange to oscillate, turning back and forth with each cycle of piston reciprocation. Such an arrangement presupposed two-cycle operation and provided a further limitation in what the valve, being located within the combustion chamber, was directly exposed in its entirety to the full heating effects of exhaust gas temperatures and corrosive effect of gases therein.
In U.S. Pat. No. 3,989,025 which issued only in 1976, Franco proposed a valve system wherein rotary valves were located on a transverse shaft parallel to the crank shaft and wherein the rotary valves, one for each of multiple cylinders, were each constructed of pressed graphite whereby such valves would be self-lubricating and self-fitting despite the high temperature associated with transfer of gases relative to the combustion chamber.
Among the problems of such prior art, as well as the many existing types of internal combustion engines which have utilized tulip valves and other more conventional designs, it is apparent that there is typically a complicated valve drive arrangement involving high friction forces, inefficiency, mass with excessive inertia, inefficiency with attendent loss of horsepower, and thermal problems. Thus, such valves of prior art designs are prone to being overheated and thereby being damaged by such heat, and are exposed to erosive effects not to mention the consequences of lubrication difficulties, all to the effect that the use of rotary valves in internal combustion engines has largely been abandoned.
It is an object of the present invention to provide a rotary valve mechanism and associated cylinder head design which provides an internal combustion engine with high efficiency performance, involving the kinetic occlusion of exhaust and intake gases to provide for elimination of timing gears, timing belts, chains, cam shafts, valve shafts, cams, tappets, pushrods, valve lifters, and various valve clearance adjustment mechanisms, as well as other apparatus typically associated with the exahust and inlet valve requirements of internal combustion engines.
It is a further object of the invention to provide such apparatus wherein its design principles conduce to true universality and flexibility of internal combustion engine design, being equally as well utilizable on engines of the Otto cycle (as for a gasoline or propane combustion) or the Diesel cycle, and further as being utilizable readily for engines operating according with either two- and four-stroke cycles.
It is a further object of the present invention to provide such apparatus which eliminates or reduces power losses heretofore associated and necessitated by conventional valve or valve drive mechanisms, including both conventional tulip valves as well as rotary valve designs of the prior art, being not only more efficient but also providing for a lower specific fuel consumption, it being also a related object of the present invention to permit a piston of lightened mass and reduced size for increased engine power, acceleration, reduced wear and lower costs.
Among still other objects of the invention may be noted the provision of such apparatus which allows cooler engine operation, being less prone to thermal problems of the prior art and not presenting either the frictional or the heat problems which have been heretofore associated with known valve constructions.
It is additionally an object of the present invention to provide such apparatus which is of extraordinary simplicity, making possible mass production manufacture of internal combustion engines with hitherto unachievable economy and ease of manufacture, conducing to economy, longevity of use, inherent reliability and lack of proneness to high stresses or other factors tending to cause fractures and other parts failure.
Other objects will be in part apparent and in part pointed out hereinbelow.